Sockets for flat blade pins



May 15, 1956 J. OSTRAK 2,746,024

SOCKETS FOR FLAT BLADE PINS Filed April 28, 1951 y 14- mm United States Patent SOCKETS FOR FLAT BLADE PINS Joseph Ostrak, St. Louis, Mo., assignor to Joy Manufacturing Company, Pittsburgh, Pa, a corporation of Pennsylvania Application April 28, 1951, Serial No. 223,546

9 Claims. (Cl. 339-256) My invention relates to electrical connectors and more particularly to an assembled, multi-part socket for flat blade pins.

It is important, in contacts for use with flat blade pins, to provide for a tightly pressed, face to face contact between socket and .pin, maintained under spring pressure. It is important that arrangements be provided which shall compensate for contact mislocation and for dimensional variations. It is further important to avoid arrangements which in any way interrupt or impede through conductivity due to the presence of joints or reduced cross sections, and to avoid dependence on spring elements for conducting purposes.

It is an object of the present invention to meet the standards of the last preceding paragraph through the provision of an improved socket for use with flat blade pins. It is another object of the invention to provide an improved assembled, multiwpart socket for flat blade pins. Other objects of the invention will hereinafter appear.

A preferred embodiment of the invention may include an outer conductor shell, desirably, but not necessarily, having an opening in one end for the reception of a conductor (other modes of conductor attachment would obviously serve) and in its other end a contact hole or chamber, desirably approximately semicircular in cross section. Said hole has, as shown, a flat wall at its flat side, providing for extended surface engagement with a flattened surface on a flat blade pin contact. Within the hole there will be mounted a resilient element opposite the fiat wall and providing a substantially parallel contact surface adapted to coact with the opposite side of a flat blade contact or pin and to press the latter forcibly against the flat wall surface mentioned. Desirably the resilient element may consist of a conductor element of suitable material, such as Phosphor-bronze, and having its surface opposite said flat wall surface of maximum width, and having narrow end portions rebent toward-s each other and providing resilience in the mounting of the strip, the resilient element being desirably mounted in the semicylindrical bore by cross pins of suitable material, such as brass, and fixed in the wall of the conductor shell and parallel to the flat wall. Desirably the flexure of the resilient element is at least in part in the wider portion thereof, so that a smooth curved surface overlies the cross pin nearer the open end of the socket and guides the flat blade pin smoothly into the socket.

In the accompanying drawings, in which one illustrative embodiment of the invention as it may be formed in practice is shown .in association with a flat blade contact pin:

Fig. l is an exterior view of a socket in which an embodiment of the invention is shown incorporated for purposes of illustration, together with a fragment of a fiat blade pin.

Fig. 2 is a view of the structures shown in 'Fig. '1 turned through 90, and with the socket shown in central longitudinal section on the plane of the line 22 of Fig. 1. Fig. 3 is a view similar to Fig. 2 with the pin in the socket and also shown in section.

Fig. 4 is a transverse section on the plane of the line 4-4 of Fig. 2.

Fig. 5 is an end view of the pin-receiving end of the socket.

Referring now to the drawing and noting first Fig. 1, there will be seen at 1 an end portion of a flat blade pin, and there will be seen at 2 a socket in which the illustrative form of the invention is embodied.

The socket or contact 2 is shown as of four-piece construction, including an outer conductor shell 3, an inner spring element 4, and two brass cross pins 5, 5. It will be apparent that the contact, when its assembly is complete, might perhaps rather be considered as of a two piece construction.

The conductor shell 3 may desirably be of copper and may be formed of tubing or be turned from the solid, and, in either event, will have a hole '7 for the reception of a wire 8 or the like at one end and a contact hole 1%) in the other end, with cross holes 11, 11 bored for the cross pins 5, 5. The contact hole walls are formed, as by swaging, to provide the contact hole with a finished approximately semi-circular cross section.

Actually the cross section of the contact hole is a little more than a semi-circle, for, as seen in Fig. 3, the fiat blade pins centrallongitudinal plane, in the assembled portion of the parts, substantially bisects, longitudinally, the unreduced body portion of the conductor shell. In any event there is provided a plane wall surface 15 to which the axes of the pins 5, 5 are parallel .in the assembled state of the socket.

The spring element 4 is desirably formed as a flat stamping. Phosphor-bronze is a suitable material. The ends, 16, of the spring are reduced (see Figs.'4 and 5) to permit them to occupy the relatively narrow space between a plane tangent to the surfaces of the pins '5, 5 away from the wall surface and the arcuate wall. While not limited to such precise arrangements, the spring ends may be bent back and towards each other to provide radii slightly exceeding the radii of the pins 5, 5 and so that they make angles of on the order of 15 with the wider, center portion, 17, of the spring, which portion is substantially flat until the spring is assembled in the socket element. The spring, then, comprises a wider portion, with parallel side edges, adapted to face the wall 15, and narrower, rebent end portions, also desirably with parallel side edges, with :the ends of the re'bent portions rounded, and with no sharp corners where the change in width between the wide and narrow portions occurs. The fiexure, as may be seen from Fig. 5, results in no sharp edges likely to catch the end of the pin as it is inserted in the socket. The spring is fixed in the conductor shell by cross pins 5, 5. These desirably of brass, fix the spring both axially and diametrically of the socket element 2. The spring ends are flexed, on assembly, to a much smaller angle than 15 to the central portion of the spring element, and stresses are set up which how the center of the wider portion of the spring, and cause it to take a fiat arc form (see Fig. 2) and to tend to lift towards the wall surface 15. The engaging pin 1 is of such a thickness that the spring must have its wide portion flattened and also, as a practical matter, probably also bodily moved slightly away from the wall surface 15, in order for the pin to be forced into place in the socket. The spring therefore very firmly presses the side of the pin which is towards the wall surface 15 into firm extended surface contact with the latter.

It will be evident that the socket construction described provides an unbroken leading edge of copper contact at the open end of the socket, of adequate thickness to dissipate heat generated by overloads and minimize the efiects of arcing. The whole of the contact material is available for increased current carrying capacity. The

large flat surface area in contact with the pin blade and firm spring pressure greatly reduce the millivolt drop found with earlier contacts. The whole structure is rugged, and its single moving part 'is well housed and protected against mechanical and electrical damage.

It will have been noted that the spring and the flat wall are closer together at their nearest points than the thick- ,ness of a flat blade pin for the reception of which the socket is provided. It will further have been noted that the socket element, when formed as illustrated in the drawing, has the chamber therein provided with an armate wall which is coaxial with an outer arcuate wall of the socket element. Because the rebent ends of the spring have to be received in a rather confined segment shaped space, disposed between a plane contacting the sides of the pins away from the fiat wall of the socket, and the adjacent arcuate internal surface of the chamber, they must'be substantially reduced in width. All of these features contribute to the efficiency and durability of the contact structure.

While there is in this application specifically described one form which the invention may assume in practice, it will be understood that this form is shown for purposes of illustration and that the invention may be modified and embodied in various other forms without departing from its spirit or the scope of the appended claims.

What I claim is:

1. In a connector, a socket element having formed in one end thereof a hole for the reception of a fiat blade pin, and providing a flat surface extending along one side of said hole and forming a portion of the peripheral boundary of said hole, said socket element having extending generally longitudinally of and loosely constrained within said hole an elongated spring in spaced relation to but arched toward said fiat surface and having at each end thereof a connection with said socket element providing for relative movement upon flattening of said spring, said surface and spring closer together at their nearest points, in the absence of such a pin from said hole, than the thickness of a flat blade pin receivable in said hole and adapted to engage concurrently the flat opposite surfaces of such a pin, said spring having oppositely bent end portions and supported at both ends within said hole in all positions thereof whether or not said flat blade pin is in inserted position within said hole or said spring is flattened as aforesaid.

2. In a connector, a socket element as defined in claim 1, in which said fiat surface extends chordally of the socket element and said hole also has an arcuate bounding surface and the outer peripheral surface of said socket element and said arcuate bounding surface are coaxial throughout their arcuate extents, said spring having oppositely rebent ends engaging said arcuate bounding surface of said hole in all positions of said spring within said hole, said rebent ends reacting against said hole-bounding surface during flattening of said spring as aforesaid and said spring being supported at its rebent end portions against said hole-bounding surface in its flattened position as aforesaid.

3. In a connector, a socket element having formed in one end thereof a hole for the reception of a flat blade pin provided with fiat sides, and providing a flat wall extending along one side of said hole, an elongated bowed spring extending generally longitudinally of and loosely constrained in said hole in spaced relation to but arched toward said flat wall, said spring having reduced ends at the opposite extremities of a wider center, said ends rebent under said center and engaging the wall of said hole at a point opposite said fiat wall, and means for constraining said spring, adjacent each of said extremities, in the hole of said socket element including transverse pins mounted at their ends in said socket elesaid spring relative to which said ends are rebent in posi tions closer to the wall opposite said fiat wall than the distances between the extremities of the rebent ends of the spring and its wider center when said spring is unconfined, said wall and spring closer together at their nearest points than the thickness of a flat blade pin receivable in said hole and adapted to engage concurrently the fiat opposite surfaces of such a flat blade pin.

4. In a socket for cooperation with a flat blade pin provided with flat sides, in combination, a socket body having one end thereof bounded exteriorly by cylindrically curved surface and a flat chordal surface, and having a chamber therein open at one extremity thereof and of a cross section similar to, but smaller than, that of said end, said chamber having an arcuate bounding surface and having a flat bounding surface parallel to said flat chordal surface and a pair of transverse pins parallel to and spaced from said second flat surface, and an elongated spring extending generally longitudinally of and loosely constrained in said chamber, said spring loosely engaging and positioned by said transverse pins and having rebent ends confined in the space between a plane tangent to the sides of said pins away from said second flat surface and said arcuate bounding surface and loosely maintained by said pins at a smaller angle to the portion of said spring between said rebent ends than such rebent ends would occupy if unconstrained.

5. In a socket as defined in claim 4, the arrangement in which the rebent ends of the pring are so stressed by fiexure that the spring, between its rebent ends, is bowed at its portion lying towards said second flat surface, said bowed portion flattening out against the contacting side of such blade pin as the latter is inserted into said chamber.

6. In a socket as defined in claim 4, the arrangement in which the spring is cut away laterally at the sides of its rebent ends for free reception in the space mentioned, said cut away sides increasing the resilience of the spring and said rebent ends yielding toward the chamber-wall as said blade pin is inserted into said chamber.

7. In a socket for cooperation with a flat blade pin having opposite flat sides spaced a predetermined distance apart, a socket body having an opening formed therein for the reception of such a pin, one boundary of said opening comprising a flat surface spaced from the axis of said body one-half of said predetermined distance, and a spring device arranged entirely in said opening and extending generally longitudinally of and loosely constrained in said opening, said spring device having an elongated opposed surface contactable with a flat side of such a pin and opposite end portions, said opposed surface spaced throughout its length from said flat sur face of said opening and nearer said flat surface, at least centrally of its own length, than said predetermined dis tance, said spring device yielding as said pin is inserted in the narrow space between said flat surface and said surface of said spring device to permit entry of said pin into said opening, said spring device when in yielded posi' tion being supported at its opposite end portions within said opening.

8. In a socket as defined in claim 7, a construction in which said spring device consists of a resilient member having its surface which is contactable with a pin convex towards said fiat surface, said convex surface flattening out against the contacting flat side of such a pin as the latter is inserted into said opening, said spring device when flattened out as aforesaid having its end portions in supported contact with a boundary of said opening.

9. In a connector, a socket element having formed in one end thereof a hole for the reception of a flat blade pin, and providing walls including a flat wall extending longitudinally along one side of said hole and forming a bounding surface for the latter, an elongated spring having opposite end portions and disposed generally longitudinally of and loosely constrained within said hole in spaced relation to but slightly arched towards said fiat wall, the arch of said spring closer at its longitudinal center to said wall than the thickness of a flat blade pin receivable in said hole and adapted to engage said fiat wall and said spring concurrently, and the ends of said arch spaced from the opposite Wall of said hole, said spring yielding within said hole away from said flat wall as said pin is inserted into the hole to cause said arched surface to flatten out against the contacting flat side of the pin, and means for loosely constraining said spring within said hole, said spring, when said pin is in inserted position in said hole and said spring is maintained in yielded position by said pin, being supported at its opposite end portions against a wall of the hole.

References Cited in the file of this patent UNITED STATES PATENTS 1,291,933 Kuhn et a1 Jan. 21, 1919 Fredericks Aug. 9, 1921 Russell Mar. 31, 1925 Maag-Eckenfelder June 28, 1932 Blomquist Nov. 8, 1932 Bauroth Aug. 8, 1939 Wade Ian. 8, 1946 Buell Aug. 12, 1947 Ostrak Dec. 6, 1949 Riche Apr. 1, 1952 Batcheller June 10, 1952 FOREIGN PATENTS Great Britain Nov. 15, 1923 Switzerland Nov. 16, 1928 Switzerland Oct. 1, 1937 Great Britain Sept. 24, 1941 

